Functionally graded chitosan ferrite beads for photocatalytic degradation of Eriochrome Black T and Congo red dyes

Abstract

Recently, semiconductor materials have attracted significant interest due to its remarkable catalytic activity. Heterogeneous catalysts play a crucial role in degrading organic dyes and their hazardous by-product, which threaten both aquatic and terrestrial ecosystems when released into wastewater. In this study, we follow the co-precipitation technique to synthesize cobalt-ferrite (CoFe₂O₄) and nickel-ferrite (NiFe₂O₄). Subsequently, produce five distinctive nanocomposite beads, decorated with chitosan: Chi-CoFe₂O₄ − I, Chi-CoFe₂O₄ − II, Chi-NiFe₂O₄ − I, and Chi-NiFe₂O₄ − II, all within an acidic aqueous environment. Different characterization was performed specially the Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) analysis, to check the morphology of the synthesized beads. Most importantly, the synthesized novel beads were then utilized for the photo-degradation of Organic dyes, mostly used in industries, i.e., Eriochrome black T (EBT), and Congo red (CR). The remarkable results revealed a staggering 93% degradation of EBT dye after just 120 min under visible light exposure. Simultaneously, CR dye shows an impressive 93% degradation just within 120 min, through Chi-NiFe₂O₄ − II. While, the TOF were 1257.5 kg⁻¹ s⁻¹, 1287 kg⁻¹ s⁻¹, 1318.18 kg⁻¹ s⁻¹, 1363 kg⁻¹ s⁻¹, and 1393 kg⁻¹ s⁻¹. Furthermore, the turnover numbers were 2.26 × 10^7 kg⁻¹ s⁻¹, 2.3 × 10^7 kg⁻¹ s⁻¹, 2.37 × 10^7 kg⁻¹ s⁻¹, 2.45 × 10^7 kg⁻¹ s⁻¹, and 2.5 × 10^7 kg⁻¹ s⁻¹ for chitosan beads, Chi-CoFe₂O₄ − I, Chi-CoFe₂O₄ − II, Chi-NiFe₂O₄ − I, and Chi-NiFe₂O₄ − II respectively. This study shows the great potential of synthesized nanocomposite beads for degrading organic dyes from wastewater. This study will be a great addition to future environmental studies.